| Objective:131I plays an important role in the treatment of differentiated thyroid carcinoma (DTC) and its metastasis, 131I therapy was chosen at first for DTC patients with cervical lymphatic metastasis and can achieve favorable effect. Tumor cell hypoxia is crucial in clinical treatment, the tumor tissue lacking of oxygen is less sensitive to the rays, and can maintain proliferation activity, leading to failure, recurrence or metastasis of tumor. Sodium glycididazole is a radiation sensitizer which has been widely used in external radiation for solid tumors. It has been introduced into 131I therapy for DTC in preliminary studies. Studies showed that sodium glycididazole could enhance sensitivity of DTC and metastatic lesions to the rays. It was not seen references involving accumulated radiation damage. Our study is to observe the changes of lymphocyte micronucleus and chromosome aberration rates in the DTC patients of thyroidectomy or with cervical lymphatic metastasis and to assess the radiation damage and recovery of patients after 131I treatment.Methods:60 cases (13 males and 47 females, 21-62 years) of thyroidectomy or with cervical lymphatic metastasis after 131I treatment were included. All the cases were confirmed by pathology, 51 cases were papillary thyroid carcinoma, 9 cases were follicular carcinoma; the mean age was 42.6±7.5 years, all cases were confirmed that there was no other distant metastases except neck lymphnode. Iodine and thyroid hormone drugs have been strictly forbidded after surgery. The 131I uptake value were higher than 1%. The interval was at least six months between the initial 131I treatment and re-treatment time for thyroid carcinoma patients. Patients were divided into three groups according to different dosage of 131I (4.44GBq,3.70GBq) and grant sodium glycodidazolum combination therapy (the group of 4.44GBq, the group of 3.70GBq, the group of 3.70 GBq with sodium glycididazole). PHA solution was added into 1ml peripheral blood collected at 1 day before 131I treatment, 7 days,3 months and 6 months after 131I treatment respectively to let lymphocyte re-transformed into lymphoblastoid with proliferation capacity. A large number of mitotic cells were acquired after short-term culture in vitro. The first mitotic peak was at 46h, then spindle inhibitor colchicines were added and culture was terminated at 50h in order to make splitted lymphocyte cells stop at metaphase. Lymphocyte suspension was collected, smeared, stained and the rates of peripheral blood lymphocyte micronucleus and chromosome aberration were detected (2000 lymphocytes and 1000 lymphocytes metaphase were observed, lymphocytes conforming to following standard can be deemed as normal: rate of micronucleus <4‰, rate of chromosome aberration <2.5%, rate of"disome and chromosome ring frequency"<0.05%); 20 cases of Graves patients were chosen as hyperthyroidism treatment group, 131I was adopted orally (the mean dose was 111MBq ~ 296MBq, 10 males and females respectively). Administration of medication and blood collection were carried out during the same time with the same measure as that of carcinoma group. All cases had no experiences of chemotherapy, radiotherapy, or exposure to radiation recently.Results:Lymphocyte micronucleus and chromosome aberration rates of all patients were at normal level the day before 131I therapy, there was no significance differences between carcinoma group and hyperthyroid group (p> 0.05); lymphocyte micronucleus, chromosome aberration rates and"disome and chromosome ring frequency"of hyperthyroid patients at all time points (7 days, 3 months, 6 months) were in the normal range after 131I therapy was treated, there was no obvious change comparing to that before 131I administration(p>0.05); For the group of thyroid carcinoma treated with 4.44GBq, thyroid carcinoma treated with 3.70GBq and thyroid carcinoma treated with 3.70GBq and sodium glycididazole, the lymphocyte micronucleus, chromosome aberration rate and the "disome and chromosome ring frequency"increased significantly at the 7th day point after 131I administration, and there was statistical significance comparing to that before 131I administration. (p<0.05); there was no statistical significance between 131I treatment group with 3.70GBq and sodium glycididazole with 3.70GBq (p>0.05); Meanwhile, there was no statistical significance between the group of 4.44GBq and 3.70GBq of 131I treatment (p>0.05). Lymphocyte micronucleus and chromosome aberration rates of 96.67% (58/60) patients restored to normal range at the 3rd month point after treatment, there was no significance between these two groups (p>0.05). However, the results of two males were still abnormal (they were in group of 4.44GBq and group 3.70GBq respectively). The lymphocyte micronucleus and chromosome aberration rates of these two males were still higher than normal level at the 6th month after treatment and they restored to normal level till the 12th month after treatment.Conclusion:1: Lymphocyte micronucleus and chromosome aberration rates of DTC patients rise in the short-term (7 days) after 131I therapy (3.7GBq, 4.44GBq); the lymphocyte micronucleus and chromosome aberration rates of most patients (95%) restored to normal level within 3 months; the rest of them restored to normal within 12 months; 2: Lymphocyte micronucleus and chromosome aberration rates of DTC patients rise in the short-term (7 days) after 131I therapy combined with sodium glycididazole (3.7GBq); Lymphocyte micronucleus and chromosome aberration rates of all the patients restored to normal level within 3 months; 3 there was no significant difference of lymphocyte micronucleus and chromosome aberration rates between different doses of 131I (3.7GBq, 4.44GBq) and 131I therapy combined with sodium glycididazole (3.7GBq); 4, there was no change in lymphocyte micronucleus and chromosome aberration rates of hyperthyroidism patients before and after 131I therapy(111MBq ~ 296MBq).
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